Certain prior art such as EP 2 198 991 A1 relates to a machine tool having a C-shaped machine frame, which has an upper frame leg and a lower frame leg. At the free ends of the two frame legs there is provided a processing station which itself includes an upper tool receiving member on the upper frame leg and a lower tool receiving member on the lower frame leg. In a leg intermediate space between the upper frame leg and the lower frame leg, there is provided a coordinate guide with a horizontal transverse rail which extends in the transverse direction of the two frame legs and which can travel in both axial directions of a horizontal movement plane in a motor-driven and numerically controlled manner. A plurality of clamping claws and a plurality of tool retention members are fitted beside each other along the transverse rail of the coordinate guide. The clamping claws serve to releasably fix a metal sheet to the transverse rail. The tool retention members form a tool store which is provided on the transverse rail and which is intended for receiving processing tools. A metal sheet which is fixed to the transverse rail by the clamping claws is positioned for processing purposes by corresponding movements of the transverse rail with respect to the processing station and the processing tools which have been introduced into the tool receiving members of the processing station. Furthermore, the transverse rail travels with respect to the processing station of the machine frame into positions in which, in order to change tools, processing tools are transferred between the tool receiving members of the processing station and the tool store provided on the transverse rail.
Depending on the respective processing task, the tool store on the transverse rail must be provided with processing tools. To this end, the transverse rail is moved on the machine frame of the previously known machine tool into a fixedly predetermined setup position at the rear end of the leg intermediate space between the upper frame leg and the lower frame leg of the machine frame. In this instance, the transverse rail moves into the fixed setup position before or after a workpiece processing operation or also before or after a tool change at the processing station. If the transverse rail is in the setup position, the tool retention members provided on the transverse rail are accessible for a tool handling device which itself is formed by a metal sheet loading and unloading unit of the previously known machine tool. The metal sheet loading and unloading unit transfers processing tools between the tool store on the transverse rail and a stationary tool magazine which is spaced apart from the machine frame of the machine tool. To this end, the metal sheet loading and unloading unit moves into a transfer/receiving position in which it can access the respective tool retention member of the transverse rail.
During the setup of the tool store on the transverse rail, the transverse rail is stationary. The sheet processing operation at the processing station of the machine tool is interrupted and a tool change at the processing station is not possible.